Mountaineer, anywhere around the islands is a good place to start. I've had most of my smallie success on the east side of Kelly's Island, just off the airport, but have also caught quite a few around the north side. Tube jigs are my bait of choice... anything dark in color, but I always do best with black/red flake or smoke/red flake.
Back in '07 I was part of a round goby study with one of my advisors from college. We dove around the islands surveying round goby populations, collecting mussels, and collecting crayfish. I learned a lot about the underwater structure near the islands during those couple weeks, and how the smallies relate to that structure. On a typical sonar unit it's difficult to really see, but there are actually cobblestone "belts" that run almost parallel to the shoreline. Sometimes they're close together, sometimes they're far apart... sometimes they're thin, sometimes they're wide. Find one of these "belts" and you will find the smallies, and lots of them. The coolest part of those couple weeks of research was the fact that smallmouth bass don't seem to be afraid of scuba divers. As I swam along the bottom, it wasn't unusual for a school of 6-10 smallies to follow me along... especially while turning over rocks looking for crayfish. These fish would damn near take a crayfish right out of my hand down there. It was an awesome experience.
Fishing for smallies in the spring is usually the most fun, but check the regs because there's a certain time period when you're not allowed to keep any. The reefs in the western basin can be decent in the spring, too. I don't think they are as concentrated on the reefs, though. If you want to fish the reefs, give Crib reef a try... be careful though because there is one spot over it where it gets REALLY shallow... shallow enough to eat props.